This invention relates to a system which uses a computer to carry out diagnosis of troubles which may occur in devices installed at users' premises and in particular to the technology of carrying out remote diagnoses of troubles in such devices by using a trouble-diagnosing computer set at their maker's place.
Recently, there is an increasing number of devices for analysis and measurement, as well as industrial apparatus, consisting of a main part and a computer for carrying out control processes. As devices and apparatus are becoming highly complicated, it is common to add a computer part to them for driving the main part and carrying out analysis of data obtained by operating the main part. If any trouble occurs in such a highly complicated apparatus installed at a user's place, however, it is often the case that the user alone cannot attend to it. In part for this reason, makers of such sophisticated apparatus nowadays are required to provide a user-support system such that any trouble which may occur can be quickly acted upon. Many makers are now equipped with a trouble-diagnosing computer installed at their own premises so as to maintain a direct access to the computer parts of the users' apparatus through a modem or a local area network (LAN) such that the nature of the trouble can be grasped in real time, for example, by driving the apparatus from the maker's computer and that the trouble can even be eliminated from a distance.
Prior art systems for such remote diagnosis have not been satisfactory for several reasons. Firstly, it was not possible to serve a plurality of users simultaneously, the maker's computer often becoming occupied for a long time with the work for one of the user's. Secondly, the telephone bill may become significantly large if the maker and the user are far apart. If the maker and the user are very far apart, say, in different countries, their working hours may be different such that there may be nobody at the maker's premises when a user experiences a trouble. When there is a possibility that sensitive data such as a trade secret may leak out, depending on the manner of connecting telephone lines (such as whether an operator serves to connect the lines) or whether the computers of the maker and the user are directly connected, the setting of a system for remote diagnosis itself becomes a difficult problem.